1. Field of the Invention
The present invention relates to a signal processing apparatus that performs, in software, a signal process composed of a plurality of signal processing units.
2. Description of the Related Art
With ever-higher performance, computers can now play back moving images and music, the playback of which was difficult before. Moving images and audio signals are currently easily real-time processed without using a dedicated signal processing device and dedicated hardware, such as a digital signal processor (DSP).
A variety of signal processing middleware techniques support the signal processing applications. For example, DirectShow is available from Microsoft® (see http//msdn.microsoft.com/library/default.asp?url=/library/en-us/directx9_c/directX/htm/directshow.asp), MATLAB is available from the MathWork® (see http://www.mathworks.com/), and Max/MSP is available from Cycling'74 (see http://www.cycling74.com/products/maxmsp.html).
The function of the signal processing application is relatively easily performed by using such middleware techniques. For example, audio signals are recorded, replayed, input and output, mixed, and subjected to special effects using the signal processing applications. As for moving images, signal processing applications having sophisticated editing functions such as non-linear editing are provided.
Applications having a plugin structure have been proposed as this type of middle ware (see Japanese Unexamined Patent Application Publications Nos. 2001-109628 and 7-302195). The plugin here refers to a modularized function, and is a software application program. Throughout this specification, the plugin refers to a software application program forming a signal processing module.
With plugin, a user can use a required signal processing module in an add-on manner as necessary. The plugin is typically used as a unit. Currently available several new systems provide a complex function by combining a plurality of plugins. Such a complex plugin system is expected to become a majority of systems creating a new value.